Can EEG (Electroencephaolography) Be Used as a Diagnostic Tool?

Some say yes, some say no, many say maybe.

First, let’s examine what Electroencephaolography (I’m going to call it an EEG, its way easier to type that) is. Electrodes are painlessly stuck to your scalp (this sucks if you have long hair, washing the goop out later) to detect electrical activity in your brain(1). There are always active brain cells, even when you’re sleeping. This test is commonly used to rule out seizure disorders, or determine what part of the brain is causing the seizure.

However, an EEG is not for use to diagnose mental illness, but there are studies that show the electrical circuits in the brain that are different in the mentally interesting than the “normal population”.

The EEG was used to test schizophrenics, a condition similar to bipolar disorder that has a “hybrid” of schizoaffective disorder. The study of patients indicates a higher number of them with abnormal records decreased in alpha activity. There are left side abnormalities, and some coherence abnormalities. (2) Further testing needed.

This study(3) claims that schizophrenia can be diagnosed before major symptoms happen, using EEG technology.



“What we found, in terms of disease, was quite striking – defects in the genes that encode these human synapse proteins are really a major cause of disease,” he said. “There are over 135 nervous system diseases, psychiatric and neurological, that arise because of defects in these synaptic proteins. These are common and rare diseases – schizophrenia, bipolar disorder, autism.”

Although there are those doubting the EEG being used a diagnostic tool, it could help in the future as research continues, to decide on the best medications to use, and also to create new medications.


Different Diagnosis and Co-morbid Disorders

Differential Diagnosis

Determination of which one of two or more diseases with similar symptoms is the one from which the patient is suffering. Also called differentiation.” (1)


Other conditions to be considered before a bipolar disorder diagnosis are as follows:(2)


Epilepsy is a disorder of the brain caused by sudden, large discharges of electrical impulses from brain cells. This disturbance affects the brain’s normal functions and produces changes in a person’s movement, behavior or consciousness.


Fahr Disease

A rare, inherited, progressive brain disorder that is characterized clinically by involuntary movements, prolonged muscle contractions, anddementia. It is characterized by abnormal deposits of calcium in the basal ganglia and cerebral cortex of the brain. There is no cure for Fahr syndrome.Treatment is directed toward relieving symptoms.



As HIV and AIDS progress, many symptoms show up, some of them mental, including mood swings, depression and suicidal ideation.


Brain Tumor/Head Injury

Any condition affecting the central nervous system can affect emotional stability as well.



Many people don’t see a doctor when they’re manic, because it has a tendency to feel good, but they’ll go during a depressed episode. Often, the bipolar disorder is “missed” and they are given medications for depression (usually an SSRI or SNRI) which can cause irritability, anger, and mixed or manic episodes.


Circadian rhythm desynchronization

An interruption in the regular recurrence in cycles of about 24 hours from one point to another, such as certain biological activities that do this regardless of long periods of darkness or other changes in environmental conditions.


Sodium Imbalance

Too much or too little sodium in the system can cause drastic mood swings, confusion and irritability.


Cushing syndrome

This is an imbalance in the pituitary gland, which is part of the brain(6). This causes depression by causing hormonal and metabolism changes, which can cause dramatic mood swings, or just major depression.


Hyper or hypothyroidism

If too much of the hormone is found, it causes nervousness. If too little of it is found, it can cause extreme fatigue.


Multiple Sclerosis

MS damages white matter in the brain, in that the central nervous system controls most of the bodies functioning. It most commonly mimics bipolar disorder.



If syphilis (an STD) reaches the brain, it can cause dementia and other psychiatric disturbances.


Lyme Disease

This is a serious bacterial infection that in late stages, affects the neurology of the brain causing, depression, psychosis and bipolar-like mood swings.



Lupus is an autoimmune (the body attacking itself)| disease which can affect the central nervous system functioning.


Co-morbid Disorders(3)

Most (95%) of the respondents with BPD in the National Comorbidity Survey met criteria for 3 or more lifetime psychiatric disorders(4)



Anxiety is often diagnosed with bipolar disorder and it can have devastating effects on treatment and diagnosis. There can be social impairment and the risk of suicide is much higher.(7)


Substance abuse disorder

Up to 50% of those diagnosed with bipolar disorder have abused substances in their life. They are often self medicating(8) but some of the symptoms of substance use disorder are the same as bipolar disorder, such as poor impulse control and poor judgement.



21.2% of those diagnosed with ADHD also meet the criteria for bipolar disorder.

One study found that the symptoms of elation, grandiosity, flight of ideas/racing thoughts, less need for sleep, and hypersexuality were best for distinguishing between ADHD and bipolar disorder in a sample of prepubertal and adolescent youth. However, this same study found that the symptoms of irritability, hyperactivity, accelerated speech, and distractibility were all common in both bipolar disorder and ADHD, and were therefore not as useful for making good differential diagnoses.”


Cluster B personality disorders

Because of their overlapping phenomenology and mutually chronic, persistent nature, distinctions between bipolar disorder and cluster B personality disorders remain a source of unresolved clinical controversy. The extent to which comorbid personality disorders impact course and outcome for bipolar patients also has received little systematic study.”(10)

Borderline personality disorder is often misdiagnosed or comorbid with bipolar disorder.


Cardiovascular disease

There is a link between the heart and mind and bipolar patients are more likely to die of cardiovascular disease than people that are not mentally interesting. It is frequently undiagnosed and treated.(11) Those will bipolar disorder should get regular physicals and have their hearts checked more than those without bipolar disorder. (EKG, echo, stress test, and so on)


Type 2 diabetes mellutis and other endocrin disorders

Because their bodies cannot regulate blood sugar and glucose, so the high’s and low’s in blood sugar can cause irritability, fatigue, and other symptoms associated with depression or bipolar disorder.



47% of people that have migraines are clinically depressed(12). Bipolar disorder and migraines is, in fact, a subtype of bipolar disorder itself.


Eating disorders

Studies show that there is an associated between subthreshold bipolar disorder and eating disorders, particularly in adolescents, and between hypomania and eating disorders, especially in binge eating disorders, which is more likely to be an adult. Clinical studies show that many with bipolar disorder overlap with eating disorders. There are many parallel’s between bipolar disorder and eating disorders, such as: eating dysregulation, mood dysregulation, impulsivity and compulsivity, craving for activity or exercise.(13)

* I personally suffered from an eating disorder for 8 years: ED-NOS and my moods were most turbulent through those times.



11% to 39% of those with bipolar also qualify for the diagnosis of Post Traumatic Stress Disorder.(14)

Many with bipolar disorder have had traumatic experiences in life, for example, taking a serious risk during a manic episode.


Before a diagnosis is made, all other conditions must be ruled out. On average, it takes five years to get a correct bipolar diagnosis.(5)

















Bipolar Disorder vs. Epilepsy

How are they connected?

 Epilepsy is a condition in the brain that causes seizures or brain dysfunction due to excessive neuron discharge. Psychiatric disturbances are common in epilepsy.

 Mood disorder’s are often comorbid with epilepsy, these two conditions share many biochemical and pathophysiological underpinnings, such as kindling, change in neurotransmitters, and modifications in messenger systems1. Both are episodic conditions that can worsen over time (kindling) and become chronic. Mood instability is frequent in those with epilepsy, but they don’t always meet the criteria for an actual affective (mood) disorder. There is a link between neurobehavioural disorders and temporal lobe epilepsy, as well as a strong link with complex partial epilepsy2.

I’m not going to get into excessive definitions of epilepsy, as this is a bipolar blog, but I will try to be as descriptive as possible.

 One problem with the consensus that epilepsy is comorbid with mood disorders is that the sampling could be incorrect because of inadequate control groups. But for the most part, professionals believe the link between mood disorders and epilepsy is quite strong, though a few disagree.

In studying the relationship between epilepsy and psychiatric disorders, care must be taken to differentiate between the following:

  • Psychiatric disorders caused by the seizures of the epilepsy – Ictal disorders, postictal disorders, and interictal disorders
  • Epileptic and psychiatric disorders caused by common brain pathology
  • Epileptic and psychiatric disorders that happen to coexist in the same patient but are not causally related

Factors in the relationship between epilepsy and behavioural & mood disorders

Epilepsy and mood disorders share a neuropathology3 , genetic predisposition and developmental disturbances. There can be problems with hormones and alteration of receptor sensitivity (receptors not working the way they should). Both could be caused by complications of medical or surgical treatment., and consequence of psychosocial burden of epilepsy itself2.


Because of the phenomenology of epilepsy, the close association between epilepsy and psychiatry has a long history. The traditional approach to epilepsy care has been to focus on the seizures and their treatment. Concentrating only on the treatment of the seizures, which occupy only a small proportion of the patient’s life, does not seem to address many of the issues that have an adverse impact on the quality of life of the patient with epilepsy.”


20-30% of those with epilepsy have psychiatric disturbances of some kind. Tucker reports that 70% of those with complex partial epilepsy met criteria for at least one disorder in the DSM. 58% of those patients suffered from depression, 32% had an anxiety disorder and 13% had psychosis. The most common conditions in epilepsy are depression, anxiety and psychosis.

There is a risk of psychosis in epilepsy 6-12x’s that of the general population.

Psychiatric Disorder


Patients With Epilepsy

Major depressive disorder



Anxiety disorder



Mood/anxiety disorder



Suicidal Ideation







A number of studies have demonstrated that affective disorders in epilepsy represent a common psychiatric comorbidity; however, most of the classic neuropsychiatric literature focuses on depression, which is actually prominent, but little is known about bipolar depression, and very little about mania, in epilepsy4


The Frontal Lobe

According to NAMI, bipolar disorder is caused by a chemical imbalance in the frontal lobe of the brain. In a manic state, activity in the frontal lobe increases signifigantly5. With depression, activity in the frontal lobe decreases. MRI’s show that there are small inconsistencies in the white matter of the brain, caused by loss of myelin.


Frontal lobe epilepsy is the second most common type of epilepsy, with temporal lobe epilepsy being the first6. It is often genetic. The frontal lobes are large areas that control a good portion of the brain and body, so when a seizure begins in the frontal lobes, it goes haywire and spreads to other parts of the brain causing a tonic-clonic (lying on the ground jerking around) seizure.


How does that relate them?

Because the same area of the brain is affected, mood stabilizers (except for lithium) called anti-consultants can work on someone with bipolar disorder and someone with epilepsy. There is little known on exactly why this happens. The two conditions can be considered comorbid because the same medications can be used to treat them. (And many with epilepsy are also mentally ill)



The class of medications, anti-consultants, target the same area of the brain for epilepsy and bipolar disorder. The medications target the GABA and glutamate neurotransmitters. Glutamate in high amounts is associated with bipolar disorder mania and epilepsy. This relates them because the same neurotransmitters are targeted and dysfunctional7. Bipolar disorder and epilepsy can also occur after a head injury. Estrogen also makes bipolar disorder and epilepsy worse.



So there you have it, links between epilepsy and bipolar disorder. There still needs to be a lot of research done, but evidence is pointing that the two may be comorbid (existing together) conditions.





  3. A deviation from the norm in the nervous system